Etymotic Research er-4b Volantino

are popular among audiophiles for personal listening
(e.g. CD and MP3 players). ER-4 earphones are high
fidelity transducers developed specifically to combine
flat frequency response with isolation from external
noise. They deliver transparent, reference quality
sound and provide at least 20-25 dB of external noise
exclusion at all frequencies, which allows listeners to
hear the full dynamic range of recorded or live music
at safe levels. Many stage performers and recording
engineers use ER-4 earphones as in-ear monitors to
monitor or isolate their own and others’ instruments
or voices from the rest of the band or mix.

Earphones are a low-cost version 

of the ER-4 earphones, with a higher accuracy 
score than all other earphones and earbuds in their
class. Sound Isolation is 15-20 dB. With a special
adapter, ER-6 earphones can plug directly into your
Musicians Earplugs.

In the late 1970s 

Elmer Carlson, an engineer 
at Knowles Electronics,
developed what we now 
call Musicians Earplugs.
His design replicated the 
natural response of the ear
canal so that sound heard with
these earplugs would have the same 
quality as the original, just quieter.

In 1985, while consulting with the Chicago

Symphony Orchestra, Mead Killion, Ph.D., president
and founder of Etymotic Research, concluded that
there was a real need for Carlson’s earplugs.

The ER-9 has reduced diaphragm stiffness for 

less attenuation.

The ER-25 has an increased diaphragm stiffness 

and an acoustic-mass channel molded into the button
for more attenuation.

Earplugs were developed
to provide low-cost,
one-size-fits-most high
fidelity earplugs that can 
be used in a variety of noisy environments.

The goal of the ER-20 design was the same as for

Musicians Earplugs: to reduce noise but preserve
sound quality; in effect, to turn down the noise but 
not muffle voices, environmental sounds or music.

ER-20s use a tuned resonator and acoustic 

resistor to give essentially equal sound reduction 
at all frequencies which preserves the fidelity of 
the original sound.

EARPLUG ATTENUATION (Sound Reduction)

EARPLUG ATTENUATION (Sound Reduction)